1. Field of the Invention
The present invention relates generally to the fields of electrochemical synthesis and microbiology. More particularly, it concerns methods for microbial electrosynthesis of hydrogen, organic compounds, and bioplastics and microbial populations for use in such methods.
2. Description of Related Art
World economies, in particular that of the U.S., are heavily reliant on the use of fossil-based carbon to produce many commodity chemicals and fuels. However, due to supply difficulties, the inevitable decline of these resources, increased world demand and environmental concerns, a shift away from coal and oil to alternatives such as natural gas, solar, and wind is occurring. However, most of these energy sources are either limited by fluctuations in price and availability or are nonrenewable as in the case of natural gas. These factors have encouraged research into the development of renewable energy technologies powered by microbes. Of particular interest are microorganisms that can capture the global greenhouse gas CO2 and convert it to a valuable commodity, such as a fuel or value-added chemicals.
Bioelectrochemical systems (BESs) include microbial fuel cells (MFCs), microbial electrolysis cells (MECs), and electrosynthetic biocathodes (Cheng et al. 2005; Logan et al. 2006; Lovely D R 2006; Rabaey et al. 2010). Of these, the bioanodes of MFCs and MECs have been the most intensively investigated. The newest and arguably most promising of these technologies is the generation of valuable chemicals by electrosynthesis. Microbial electrosynthesis requires microorganisms to catalyze the reduction of CO2 by consuming electrons on a cathode in a BES. However, to date, efficient microbial conversion of CO2 into usable commodity chemicals, such as H2, organics, and bioplastics, has not been demonstrated in a bioelectrical system.